CN110899012A

CN110899012A - Powder spray gun

Info

Publication number: CN110899012A
Application number: CN201911271530.9A
Authority: CN
Inventors: 张卫; 李绮屏
Original assignee: Zhongye Jingcheng Engineering Technology Co Ltd; CERI Technology Co Ltd
Current assignee: MCC Capital Engineering and Research Incorporation Ltd; Zhongye Jingcheng Engineering Technology Co Ltd; CERI Technology Co Ltd
Priority date: 2019-12-12
Filing date: 2019-12-12
Publication date: 2020-03-24

Abstract

The present invention provides a powder spray gun comprising: the spray gun comprises a gun body, a spray gun head and a spray gun tail, wherein the two ends of the gun body are respectively provided with the spray gun head and the spray gun tail; the powder conveying pipe comprises an inner section and an outer section, wherein the inner section penetrates through the gun body, the outer section is arranged outside the gun body and can be connected with a powder supply system, the inner section extends to the head of the spray gun from the tail of the spray gun and is communicated with a spray nozzle of the spray gun, and a gas inlet is formed in the side wall of the outer section; the gas conveying pipe is connected and communicated with the gas inlet, secondary atomizing gas conveyed by the gas conveying pipe is sprayed into the outer section from the gas inlet, and the secondary atomizing gas sprayed into the outer section and primary atomizing powder conveyed by the outer section are mixed to form secondary atomizing powder in the process of flowing towards the spray gun nozzle. The invention prolongs the mixing path of the secondary atomization gas and the primary atomization powder, so that the primary atomization powder is more fully secondarily atomized, the powder sprayed from the spray gun nozzle is more uniform, the powder is more uniformly adhered to the surface of a sprayed product, and the qualification rate of the sprayed product is improved.

Description

Powder spray gun

Technical Field

The invention relates to the technical field of electrostatic powder coating, in particular to a powder spray gun.

Background

As shown in figure 1, the structure and principle of the spray gun adopted by the existing electrostatic powder spraying are that compressed air is used as power, atomized primary atomized powder is injected into a powder supply pipe 1 'connected with the spray gun through a powder supply system, the primary atomized powder is injected from the tail part of a powder guide pipe 2' arranged in the spray gun through the powder supply pipe 1 ', the primary atomized powder is sprayed out from a spray gun nozzle 3' at the head part of the spray gun after passing through the powder guide pipe 2 ', and because the head part of the spray gun is provided with a discharge needle 4' capable of generating high-voltage static electricity, when the primary atomized powder is sprayed out from the spray gun nozzle 3 ', the primary atomized powder passes through air ionized in the air by the discharge needle 4', so that the primary atomized powder is charged, and the charged primary atomized powder is adsorbed on a spray product to realize spraying.

In addition, a front flushing air outlet 5 ' is arranged near the spray gun nozzle 3 ' and at a position less than about 50-80 mm away from the spray gun nozzle 3 ', the front flushing air outlet 5 ' is connected with an air supply pipeline specially used for supplying compressed air, the front flushing air outlet 5 ' sprays the compressed air (front flushing air) into a powder guide pipe 2 ' close to the spray gun nozzle 3 ', then the compressed air is mixed with primary atomized powder in the powder guide pipe 2 ', and the mixture is sprayed out from the spray gun nozzle 3 ', the front flushing air has two functions, firstly, the discharge needle 4 ' at the head of the spray gun is cooled, and the temperature is increased because the discharge needle 4 ' generates heat after long-time work, the powder passing through the discharge needle is easy to adhere to cause the blockage of the spray gun nozzle 3 ', and the blockage is reduced by cooling the discharge needle 4 '; secondly, the primary atomized powder passing through the nozzle 3' of the spray gun is atomized for the second time, so that the sprayed powder is more uniform, and the sprayed powder is sprayed on a sprayed product and is attached more uniformly.

The device has the problems that if the primary atomized powder output from the powder supply system enters the spray gun under the condition of not well atomized powder due to various reasons (such as that a Venturi pump does not atomize the powder), the front air sprayed from the front air outlet 5 'plays an important role in re-atomizing the powder, but because the front air is sprayed into the powder guide pipe 2' near the spray gun nozzle 3 ', the powder is sprayed out from the spray gun nozzle after being mixed with the primary atomized powder in the spray gun powder guide pipe 2' for a short flow, and the mixing path and the mixing time of the primary atomized powder are too short, the secondary atomization effect of the powder is poor, so that the powder sprayed from the spray gun is not well atomized, the powder on the surface of a sprayed product is not uniformly adhered, and the problem that the sprayed product is not qualified is easy to occur.

Disclosure of Invention

The invention aims to provide a powder spray gun to solve the problem that the existing powder spray gun has poor secondary atomization effect on powder.

To achieve the above object, the present invention provides a powder spray gun, comprising: the spray gun comprises a gun body, a spray gun head and a spray gun tail, wherein the two ends of the gun body are respectively provided with the spray gun head and the spray gun tail; the powder conveying pipe comprises an inner section and an outer section, the inner section penetrates through the gun body, the outer section is arranged outside the gun body and can be connected with a powder supply system, the inner section extends from the tail of the spray gun to the head of the spray gun and is communicated with a spray nozzle of the spray gun, and a gas inlet is formed in the side wall of the outer section; a gas delivery pipe for carrying secondary atomizing gas, gas delivery pipe with gas inlet connects and communicates, secondary atomizing gas that gas delivery pipe carried is followed gas inlet spouts into in the outer section, spout into secondary atomizing gas in the outer section with the once atomized powder that outer section carried mixes towards the in-process that the spray gun spout flows and forms secondary atomized powder.

The powder spray gun as described above, wherein a portion of the outer section between the gas inlet and the gun tail is 0 to 2000mm in length.

The powder spray gun as described above, wherein the gas duct is disposed obliquely with respect to the outer section, and an angle between an inlet direction of the gas duct and the outer section is 10 ° to 90 °.

The powder spray gun as described above, wherein the gas inlet has an offset distance from the center of the powder transport pipe in the radial direction of the powder transport pipe, the offset distance being 0 to 5 mm.

The powder spray gun further comprises a nozzle arranged at the spray opening of the spray gun and an air guide pipe which extends into the gun body and is positioned on the outer side of the inner section; the nozzle comprises an annular outer sleeve and an annular inner core fixed in the outer sleeve, the outer sleeve is connected with the inner section of the secondary atomized powder conveying pipe, a cavity communicated with the inner section and used for the atomized powder to pass through is formed between the outer sleeve and the inner core, and an annular spraying port communicated with the cavity is formed between the bottom edge of the outer sleeve and the bottom edge of the inner core; the side wall of the outer sleeve is provided with an air inlet hole, the air guide tube is communicated with the air inlet hole, an air flow channel is axially arranged inside the inner core and is communicated with the air inlet hole, the bottom surface of the inner core is provided with an air jet communicated with the air flow channel, and the air jet is surrounded by the material spraying hole.

The powder spray gun as described above, wherein the side wall of the outer sleeve is provided with a plurality of air inlets, the side wall of the spray gun head is provided with an annular cavity, the annular cavity surrounds the plurality of air inlets and is communicated with the plurality of air inlets, the air duct extends into the side wall of the gun body from the tail of the spray gun and extends to the annular cavity, and the air duct is communicated with the plurality of air inlets through the annular cavity.

The powder spray gun as described above, wherein the outer sleeve includes a first sleeve body and a second sleeve body that are separately arranged, the center of the first sleeve body has a first through hole that is axially through, the center of the second sleeve body has a second through hole that is axially through, the air inlet is provided on the side wall of the first sleeve body or the second sleeve body, the first sleeve body is connected with the inner section of the powder conveying pipe; the nozzle also comprises a centering assembly, the centering assembly comprises a positioning cylinder and a positioning core which is fixed in the positioning cylinder and is coaxially arranged with the positioning cylinder, at least one axially-through feeding channel is arranged between the positioning cylinder and the positioning core, the upper end of the positioning cylinder is coaxially connected with the first sleeve, the lower end of the positioning cylinder is coaxially connected with the second sleeve, the feeding channel is communicated with the first through hole and the second through hole, an air inlet channel communicated with the air inlet hole is arranged in the centering assembly, and the air inlet channel is not communicated with the feeding channel; the inner core is arranged in the second through hole, the upper end of the inner core is coaxially connected with the lower end of the positioning core, the cavity is formed between the inner core and the second sleeve body and is communicated with the feeding channel, and the airflow channel is communicated with the air inlet channel.

The powder spray gun as described above, wherein the positioning cylinder and the positioning core are connected by one or more wings, and when the number of the wings is plural, the plurality of wings are arranged at intervals along the circumferential direction of the positioning cylinder, and the plurality of wings divide the annular space between the positioning cylinder and the positioning core into the plurality of feeding channels, and the air inlet channel passes through the positioning cylinder and the wings in the radial direction.

The powder spray gun as described above, wherein the lower portion of the second sleeve body is a trumpet-shaped first gradually expanding portion whose inner diameter is gradually expanded along the flow direction of the secondary atomized powder, the lower portion of the inner core is a second gradually expanding portion whose outer diameter is gradually expanded along the flow direction of the secondary atomized powder, and the nozzle is formed between the bottom edge of the first gradually expanding portion and the bottom edge of the second gradually expanding portion; the air injection port is a tapered hole with the inner diameter gradually expanding along the airflow direction.

The powder spray gun as described above, wherein the nozzle is made of a metallic conductive material, and the nozzle is connected to the electrostatic generator through a wire.

The powder spray gun of the invention has the characteristics and advantages that:

1. according to the invention, the gas inlet is arranged at the position of the powder conveying pipe far away from the spray gun nozzle, and the secondary atomizing gas is sprayed into the powder conveying pipe through the gas inlet, so that the secondary atomizing gas and the primary atomizing powder in the powder conveying pipe can flow through the inner section at least and are mixed in the process before reaching the spray gun nozzle;

2. according to the invention, the air inlet hole is formed in the side wall of the outer sleeve of the nozzle, the air flow channel communicated with the air inlet hole is formed in the inner core, the air jet port is formed in the bottom surface of the inner core, compressed air is introduced into the air inlet hole during spraying, the compressed air is sprayed out from the air jet port after sequentially flowing through the air inlet hole and the air flow channel to fill a cavity formed by negative pressure generated at the bottom of the inner core due to secondary atomized powder sprayed by the spraying hole, so that not only can the powder which is not adhered and accumulated at the bottom of the inner core be blown away, but also the inner core can be cooled, the phenomenon that the powder is easily adhered due to temperature rise of the inner core can be prevented, the phenomenon that the adhered powder and accumulated powder fall off at the bottom of the inner core can be avoided, the powder tumors are generated on the sprayed product due to the falling;

3. according to the invention, through arranging the centering assembly, when the outer sleeve is assembled, the first sleeve body, the second sleeve body and the inner core are coaxially connected together by directly adopting the centering assembly, so that the outer sleeve and the inner core can be coaxially assembled, the bottom edge of the outer sleeve and the annular bottom edge of the inner core can be ensured to be two concentric circles, the spray opening is ensured to be a circular ring with uniform ring width, the assembly operation is simple, convenient and rapid, a tool is not required to be independently manufactured for assembly, a pin shaft hole is not required to be drilled, the workload and difficulty of processing and assembly are greatly reduced, and the cost is reduced.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:

FIG. 1 is a schematic view of a prior art powder spray gun;

FIG. 2 is a schematic view of an embodiment of the powder spray gun of the present invention;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2;

FIG. 4 is a partial enlarged view at B;

FIG. 5 is a schematic view of the assembly of one embodiment of the nozzle of the present invention;

FIG. 6 is an exploded schematic view of the nozzle of FIG. 5;

FIG. 7 is a schematic view of one embodiment of a centering assembly of the present invention;

FIG. 8 is a cross-sectional view of the centering assembly of FIG. 7 taken along line C-C;

fig. 9 is a top view of the centering assembly of fig. 7.

Main element number description:

100. a gun body; 110. a spray gun head; 120. the tail part of the spray gun; 130. an annular cavity;

200. a powder delivery pipe;

201. a gas inlet; 210. an inner section; 220. an outer section; 230. a powder supply pipe; 240. a powder guide pipe;

300. a gas delivery pipe; 310. a jacket; 400. an air duct;

500. a nozzle;

1. a jacket; 11. an air inlet; 12. a first sleeve body; 121. a first through hole; 122. a lower step hole;

13. a second sleeve body; 131. a second through hole; 132. an upper stepped bore; 133. a first diverging section;

2. an inner core; 21. an air flow channel; 22. an air jet; 23. inserting the column; 24. a second diverging section;

3. a cavity; 31. a material spraying port;

4. a centering assembly; 41. a positioning cylinder; 411. an annular groove;

42. a positioning core; 421. mounting holes; 422. a cone;

43. a feed channel; 44. an air intake passage; 45. a wing plate; 5. an electric wire;

1', a powder supply pipe; 2', a powder guide pipe; 3', a spray gun nozzle; 4', a discharge needle; 5', a front air-flushing air outlet.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings. Where adjective or adverbial modifiers "center," "horizontal" and "vertical," "upper" and "lower," "top" and "bottom," "inner" and "outer" are used merely to facilitate relative reference between groups of terms, and do not describe any particular directional limitation on the modified terms. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

As shown in FIG. 2, the present invention provides a powder spray gun, which comprises a gun body 100, a powder delivery pipe 200 and a gas delivery pipe 300 for delivering a secondary atomizing gas, for example, the secondary atomizing gas is compressed air, the gun body 100 has a gun head 110 and a gun tail 120 at two ends, the gun head 110 is provided with a gun nozzle, the powder delivery pipe 200 comprises an inner section 210 penetrating the gun body 100 and an outer section 220 arranged outside the gun body 100 and capable of being connected with a powder supply system, the inner section 210 extends from the gun tail 120 to the gun head 110 and is communicated with the gun nozzle, the side wall of the outer section 220 is provided with a gas inlet 201, the gas delivery pipe 300 is connected and communicated with the gas inlet 201, the secondary atomizing gas delivered by the gas delivery pipe 300 is injected into the outer section 220 from the gas inlet 201, and the secondary atomizing gas injected into the outer section 220 and the primary atomizing powder delivered by the outer section 220 are mixed to form a secondary atomized powder in the process of flowing towards the gun nozzle That is, the secondary atomizing gas and the primary atomized powder flow through the inner section 210 at least together and are mixed during the flow through the inner section 210, so that the length of the mixing path of the secondary atomizing gas and the primary atomized powder is not less than the length of the inner section 210, and the powder can be atomized more sufficiently.

According to the invention, the gas inlet is arranged at the position of the powder conveying pipe far away from the spray gun nozzle, and the secondary atomizing gas is sprayed into the powder conveying pipe through the gas inlet, so that the secondary atomizing gas and the primary atomizing powder in the powder conveying pipe at least flow through the inner section and are mixed in the process before reaching the spray gun nozzle.

As shown in fig. 2, further, a part of the outer section 220 between the gas inlet 201 and the lance tail 120 has a length L1 of 0-2000 mm, that is, the mixing path (mixing stroke) of the secondary atomizing gas and the primary atomizing powder includes the part of the outer section and the entire inner section having a length L1, further extending the mixing path of the secondary atomizing gas and the primary atomizing powder.

As shown in fig. 2, in an embodiment, the powder conveying pipe includes a powder supplying pipe 230 and a powder guiding pipe 240 connected with each other, the powder guiding pipe 240 extends into the gun body 100, the powder guiding pipe 240 has a head end and a tail end, the head end of the powder guiding pipe 240 is located in the head portion 110 of the spray gun, the tail end of the powder guiding pipe 240 is located outside the tail portion 120 of the spray gun, for example, the powder guiding pipe 240 penetrates through a central hole in the middle of the gun body 100, the powder supplying pipe 230 is located outside the gun body 100, one end of the powder supplying pipe 230 is connected with the tail end of the powder guiding pipe 240, and the other end of the powder supplying pipe 230 can be connected with a powder supplying system; the gas inlet 201 is disposed on the sidewall of the tail end of the powder guide tube 240, or the gas inlet 201 is disposed on the sidewall of the powder supply tube 230.

As shown in fig. 2, the gas conveying pipe 300 is disposed obliquely relative to the outer section 220, and the included angle α between the inlet direction of the gas conveying pipe 300 and the outer section 220 is 10 ° to 90 °, specifically, the gas conveying pipe 300 is positioned outside the outer section 220 through a jacket 310 and maintains an included angle α with the outer section 220, the jacket includes a first jacket and a second jacket, the second jacket is connected with the outer sidewall of the first jacket and is communicated with the first jacket, the central axis of the second jacket is disposed obliquely relative to the central axis of the first jacket, and the included angle between the central axis of the second jacket and the central axis of the first jacket is equal to the included angle α between the gas conveying pipe 300 and the outer section 220, the first jacket is disposed outside the outer section 220, and the second jacket is disposed outside the gas conveying pipe 300.

As shown in fig. 2 and 3, the gas inlet 201 is offset from the center of the powder transport pipe 200 by an offset distance S of 0 to 5mm in the radial direction of the powder transport pipe 200.

As shown in fig. 2, the length L2 of the gun body 100 is 200mm to 1000 mm.

As shown in fig. 2, the gas inlet 201 has a diameter of 1mm to 4 mm.

As shown in fig. 2, the pressure of the secondary atomizing gas ejected from the gas inlet 201 can be adjusted, for example, the pressure of the secondary atomizing gas ejected from the gas inlet 201 is 0.01MPa to 0.5 MPa.

As shown in fig. 2, 5 and 6, in an embodiment, the powder spray gun further includes an air duct 400 extending into the gun body 100 and located outside the inner section 210, and a nozzle 500 disposed at a nozzle of the spray gun, where the nozzle 500 includes an annular outer sleeve 1 and an inner core 2 fixed in the outer sleeve 1, the outer sleeve 1 is connected to the inner section 210 of the powder conveying pipe 200, an annular cavity 3 communicated with the inner section 210 is formed between the outer sleeve 1 and the inner core 2 for passing the secondary atomized powder, and an annular nozzle 31 communicated with the cavity 3 is formed between a bottom edge of the outer sleeve 1 and a bottom edge of the inner core 2, that is, the powder conveying pipe 200, the cavity 3 and the nozzle 31 are sequentially communicated to allow the secondary atomized powder to pass through, and the secondary atomized powder is attached to a sprayed product after being sprayed from the nozzle 31; be equipped with inlet port 11 on the lateral wall of overcoat 1, air duct 400 and inlet port 11 intercommunication, the inside of inner core 2 is equipped with airflow channel 21 along the axial, airflow channel 21 and inlet port 11 intercommunication, be equipped with the air jet 22 with airflow channel 21 intercommunication on the bottom surface of inner core 2, jet 31 encircles air jet 22, also be air duct 400, inlet port 11, airflow channel 21 and air jet 22 communicate in proper order, in order to pass through for the gas, the negative pressure cavity of filling inner core 2 bottom after gas is spun from air jet 22.

When the powder spray gun is used for spraying powder, powder and compressed air are mixed in a powder supply system to form primary atomized powder, the primary atomized powder is injected into a powder conveying pipe, and in the process of conveying in the powder conveying pipe, the primary atomized powder is mixed with secondary atomized gas sprayed from a gas inlet to form secondary atomized powder which is more sufficiently atomized, the secondary atomized powder enters from an upper inlet of an outer sleeve 1, passes through a cavity 3 and is sprayed out from a spraying port 31 between the bottom end of the outer sleeve 1 and the bottom end of an inner core 2, meanwhile, another path of gas (such as the gas is also compressed air) is injected into a gas guide pipe 400, flows through the gas guide pipe 400 and enters a nozzle 500 from a gas inlet 11 on the side wall of the outer sleeve 1, flows through a gas flow channel 21 and is sprayed out from a gas outlet 22 on the bottom surface of the inner core 2 to fill a negative pressure cavity at the bottom of the inner core 2, so that powder which, the inner core 2 can be cooled, the situation that powder is more easily adhered due to the temperature rise of the inner core 2 is avoided, the situation that the bottom of the inner core 2 is not adhered with powder and accumulated powder falls is guaranteed, powder lumps are prevented from being generated on a sprayed product due to the falling accumulated powder, the uniformity of powder on the surface of the sprayed product is guaranteed, and the reject ratio of the sprayed product is effectively reduced.

The fixing connection mode of the outer sleeve 1 and the inner core 2 may be a pin connection, and of course, other connection modes may also be used, and the invention is not limited to this.

As shown in fig. 5, the air nozzle 22 is a tapered hole with an inner diameter gradually expanding along the airflow direction, so that the diffusion effect is better when the air is sprayed out, the powder at the bottom of the inner core 2 is more easily blown away, the powder is not accumulated at the bottom of the inner core 2, and the diffusion degree of the compressed air can be controlled by controlling the size or the taper angle of the tapered hole.

As shown in fig. 5, in a specific embodiment, a plurality of air inlet holes 11 are formed in a side wall of the outer casing 1, an annular cavity 130 is formed in a side wall of the spray gun head 110, the annular cavity 130 surrounds the plurality of air inlet holes 11 and is communicated with the plurality of air inlet holes 11, the air duct 400 extends into a side wall of the gun body 100 from the spray gun tail 120 and extends to the annular cavity 130, the air duct 400 is communicated with the plurality of air inlet holes 11 through the annular cavity 130, that is, the air duct 400, the annular cavity 130, the air inlet holes 11, the air flow channel 21 and the air jet 22 are sequentially communicated, and air enters the plurality of air inlet holes 11 through the annular cavity 130.

As shown in fig. 5 and 6, in a preferred embodiment, the outer sheath 1 and the inner core 2 are connected through the centering assembly 4, specifically, the outer sheath 1 includes a first sheath body 12 and a second sheath body 13 which are separately arranged, the first sheath body 12 is located above the second sheath body 13, a first through hole 121 which axially penetrates is formed in the center of the first sheath body 12, a second through hole 131 which axially penetrates is formed in the center of the second sheath body 13, the air inlet holes 11 are formed in the side wall of the first sheath body 12 or the side wall of the second sheath body 13, in the embodiment of fig. 1, the air inlet 11 is formed on the side wall of the first sleeve 12, the first sleeve 12 is connected to the inner section 210 of the powder conveying pipe 200, for example, the lower end of the inner section 210 of the powder conveying pipe 200 extends into a stepped hole in the first casing 12, and is in interference fit with the stepped hole, thereby achieving a fixed connection of the first sleeve 12 and the inner section 210 of the powder conveying pipe 200;

the nozzle further comprises a centering assembly 4, the centering assembly 4 comprises a positioning cylinder 41 and a positioning core 42 which is fixed in the positioning cylinder 41 and is coaxially arranged with the positioning cylinder 41, at least one axially-through feeding channel 43 is arranged between the positioning cylinder 41 and the positioning core 42, the upper end of the positioning cylinder 41 is coaxially connected with the first sleeve 12, the lower end of the positioning cylinder 41 is coaxially connected with the second sleeve 13, the feeding channel 43 is communicated with the first through hole 121 and the second through hole 131, an air inlet channel 44 communicated with the air inlet 11 is arranged in the centering assembly 4, and the air inlet channel 44 is not communicated with the feeding channel 43;

the inner core 2 is arranged in the second through hole 131, the upper end of the inner core 2 is coaxially connected with the lower end of the positioning core 42, a cavity 3 is formed between the inner core 2 and the second sleeve body 13, the cavity 3 is communicated with the feeding channel 43, and the airflow channel 21 is communicated with the air inlet channel 44.

In the embodiment, the centering assembly 4 is arranged, and when the outer sleeve 1 and the inner core 2 are assembled, the first sleeve body 12, the second sleeve body 13 and the inner core 2 are coaxially connected together by directly adopting the centering assembly 4, so that the outer sleeve 1 and the inner core 2 can be coaxially assembled and automatically centered, the bottom edge of the outer sleeve 1 and the bottom edge of the inner core 2 are ensured to be two concentric circles, the spraying port 31 is ensured to be a circular ring with uniform ring width, the assembling operation is simple, convenient and rapid, a tool does not need to be independently manufactured to coaxially assemble the outer sleeve 1 and the inner core 2, a pin shaft hole does not need to be drilled to connect the outer sleeve 1 and the inner core 2, the workload and difficulty of processing and assembling are greatly reduced, and the cost; in the prior art, the centering assembly 4 is not arranged, a tool structure needs to be designed and manufactured before assembly, the outer sleeve 1 and the inner core 2 are assembled by adopting the tool structure to ensure that the inner core 2 and the outer sleeve 1 are coaxial, and the gap spacing (ring width) of the circular seam of the nozzle is ensured to be consistent, so that the manufacturing cost and the assembly difficulty are increased;

in addition, in the present embodiment, by providing the centering assembly 4, the air inlet 11 and the air flow passage 21 can be communicated by disposing the air inlet passage 44 in the centering assembly 4, so that the air inlet passage 44 can be disposed more simply and conveniently.

As shown in fig. 5, 6 and 7, further, the air inlet channel 44 is arranged along the radial direction of the centering assembly 4, the air inlet channel 44 passes through the positioning cylinder 41 along the radial direction and extends inward to the center of the positioning core 42, the center of the positioning core 42 is provided with a mounting hole 421 along the axial direction, the upper end of the mounting hole 421 is communicated with the air inlet channel 44, the mounting hole 421 extends downward to the lower end surface of the positioning core 42, that is, the mounting hole 421 is a blind hole, the upper end of the inner core 2 is provided with the plug-in post 23, the plug-in post 23 is inserted and fixed in the mounting hole 421, the air flow channel 21 extends to the top surface of the plug-in post 23 and is communicated with the air inlet channel 44 through the mounting hole 421, by providing the mounting hole 421, the air flow channel 21 can be communicated with the air inlet channel 44, the positioning core 42 and the inner core 2 can be connected and assembled together, the structure is simple, the processing is convenient, and good centering and positioning are realized.

For example, the inserting column 23 is cylindrical, the mounting hole 421 is a cylindrical hole, and the inserting column 23 is in interference fit with the mounting hole 421, so that the processing and the assembly are convenient, and air leakage can be avoided. However, the present invention is not limited thereto, and the plug 23 may be fixed to the mounting hole 421 by other means, such as screwing the plug 23 and the mounting hole 421.

As shown in fig. 5 and 7, further, an annular groove 411 is circumferentially arranged on an outer wall of the positioning cylinder 41, a plurality of air inlets 11 are provided, the plurality of air inlets 11 are all communicated with the annular groove 411, the plurality of air inlet passages 44 are all communicated with the annular groove 411, the plurality of air inlets 11 and the plurality of air inlet passages 44 are arranged in a one-to-one correspondence or dislocation manner in a radial direction, the number of the air inlets 11 and the number of the air inlet passages 44 can be the same or different, the annular groove 411 is arranged to communicate the plurality of air inlets 11 and the plurality of air inlet passages 44 through the annular groove 411, each air inlet 11 and each air inlet passage 44 can be aligned in a radial direction or can be arranged in a dislocation manner without alignment, so that the assembly operation is simpler and more convenient, the assembly difficulty is further reduced, in addition, by arranging the annular groove 411, compressed air in the annular groove 411 can enter from the plurality of air inlet passages 44, the gas is mixed in the mounting hole 421 and then is ejected from the gas ejection opening 22, so that the gas flow direction is more stable and the diffusion effect is better. However, the present invention is not limited to this, and the outer wall of the positioning cylinder 41 may not be provided with the annular groove 411, and when assembling, the plurality of air inlet holes 11 and the plurality of air inlet passages 44 are aligned one by one in the radial direction, so that the plurality of air inlet holes 11 and the plurality of air inlet passages 44 are respectively communicated correspondingly.

As shown in fig. 7, 8 and 9, the positioning cylinder 41 is connected to the positioning core 42 by one or more wing plates 45, when the number of the wing plates 45 is multiple, the wing plates 45 are arranged at equal intervals along the circumferential direction of the positioning cylinder 41, the wing plates 45 divide the annular space between the positioning cylinder 41 and the positioning core 42 into a plurality of feeding channels 43, and the air inlet channel 44 passes through the positioning cylinder 41 and the wing plates 45 in the radial direction. For example, the number of the vanes 45 is two, four or six, the number of the feed channels 43 is two, four or six, and the number of the intake holes 11 is two, four or six. By arranging the wing plate 45, the air inlet channel 44 is convenient to arrange, the positioning cylinder 41 and the positioning core 42 are convenient to connect, the structure is simple, and the processing is convenient.

As shown in fig. 7 and 8, the wing plates 45 are further pointed at the top and bottom ends thereof to reduce resistance to the passage of powder and compressed air.

Further, the wing plates 45 are obliquely arranged relative to the central axis of the positioning cylinder 41, when the number of the wing plates 45 is multiple, the oblique directions of the wing plates 45 are the same, and the powder coating is sprayed out from the nozzle with a rotary diffusion effect in a manner similar to a circumferential array form of fan blades, so that the sprayed powder is more uniform and the atomization effect is better. For example, the included angle between the wing plate 45 and the central axis of the positioning cylinder 41 is 0-60 °, and preferably, the included angle between the wing plate 45 and the central axis of the positioning cylinder 41 is 15 ° or 30 °. However, the present invention is not limited thereto, and the wing plates 45 may be parallel to the central axis of the positioning cylinder 41 (as shown in fig. 4).

As shown in fig. 5, the top of the positioning core 42 is a cone 422 with an upward tip, and the cone 422 extends out of the positioning cylinder 41 and into the first through hole 121. By providing the cone 422, the secondarily atomized powder entering the first through-hole 121 can be uniformly dispersed into the feeding passage 43 in the centering block 4, and the resistance to the passage of the powder and the compressed air can be reduced. Specifically, the lower portion of the positioning core 42 is a cylinder, the cone 422 is connected to the upper portion of the cylinder, the cylinder is located in the positioning cylinder 41, and the feeding passage 43 is located between the outer wall of the cylinder and the inner wall of the positioning cylinder 41. For example, the cone angle of the cone 422 is 30 ° to 90 °, and preferably, the cone angle of the cone 422 is 60 °.

As shown in fig. 5 and 6, a lower stepped hole 122 is formed in the center of the lower end of the first sleeve 12, the upper end of the positioning cylinder 41 is inserted into and fixed to the lower stepped hole 122, an upper stepped hole 132 is formed in the center of the upper end of the second sleeve 13, and the lower end of the positioning cylinder 41 is inserted into and fixed to the upper stepped hole 132. Through setting up lower step hole 122 and going up step hole 132 and come the positioning tube 41, simple structure, the processing of being convenient for, assembly operation is simple and convenient, guarantees that first sleeve body 12 and second sleeve body 13 are not become flexible not to drop with positioning tube 41 assembly back, realizes fine centering location.

For example, the lower stepped hole 122 and the upper stepped hole 132 are cylindrical holes, the lower stepped hole 122 is in interference fit with the upper end of the positioning cylinder 41, and the upper stepped hole 132 is in interference fit with the lower end of the positioning cylinder 41, so that the processing and the assembly are convenient. However, the present invention is not limited thereto, and the lower stepped hole 122 and the upper stepped hole 132 may be fixed to the positioning cylinder 41 by other means, such as screwing the lower stepped hole 122 and the upper stepped hole 132 to the positioning cylinder 41.

As shown in fig. 5 and 6, in a specific embodiment, the lower portion of the second sleeve 13 is a flared first gradually expanding portion 133 whose inner diameter is gradually expanded along the flowing direction of the secondary atomized powder, the lower portion of the inner core 2 is a second gradually expanding portion 24 whose outer diameter is gradually expanded along the flowing direction of the secondary atomized powder, the shape of the second gradually expanding portion 24 is identical to the shape of the first gradually expanding portion 133, and the shape of the second gradually expanding portion 24 is umbrella-shaped, so that the inner core 2 can also be referred to as an umbrella-shaped cap, and the injection port 31 (or referred to as an outlet circular seam) is formed between the annular bottom edge of the first gradually expanding portion 133 and the annular bottom edge of the second gradually expanding portion 24. The lower part of the inner core 2 is arranged to be an umbrella-shaped structure which is gradually expanded from top to bottom, so that the secondary atomized powder entering the cavity 3 can be guided, and the secondary atomized powder can be dispersed below the nozzle more uniformly and in a larger area.

As shown in fig. 5 and 6, further, the bottom edge of the first divergent portion 133 is a sharp-angled structure, and the bottom edge of the second divergent portion 24 is a sharp-angled structure, so that the spraying effect is better, when the second sleeve body 13 is made of a metal conductive material and is connected with an electrostatic generator, the secondary atomized powder is sprayed out from the spraying port 31, passes through an electric field generated by the tip of the lower end of the second sleeve body 13, and is attached with electric charges by the electric field, so that the sprayed powder is better in atomization effect, higher in charging capability to the powder, and better in spraying effect.

As shown in fig. 5, further, the bottom edge of the second sheath 13 is higher than the bottom edge of the inner core 2, which makes the spraying effect better.

In one embodiment of the present invention, the nozzle is made of a metal conductive material, the nozzle is connected to the electrostatic generator through a wire (e.g., a high voltage electrostatic wire), and when the second sleeve body 13 is connected to a high voltage output line of the electrostatic generator, the powder coating is charged by the electric field and finally adsorbed onto the surface of the coated substrate when passing through the electric field generated at the tip of the lower end of the second sleeve body 13 when the powder coating is ejected from the nozzle. The nozzle in the embodiment can also be called an annular discharge nozzle, and the powder spray gun of the invention can also be called an electrostatic powder spray gun, and can be used in the field of electrostatic powder spraying.

In another embodiment of the present invention, the nozzle is made of a non-metallic material, such as an inorganic non-metallic material or an organic polymer material, and the nozzle of this embodiment can be used in other spray coating fields that do not require ionization.

However, the present invention is not limited thereto, and the material of each part of the nozzle may be different, for example, only the second sleeve 13 is made of a metal conductive material, and when the second sleeve 13 is connected to an electrostatic generator, it can be used for electrostatic powder spraying, and the first sleeve 12, the inner core 2 and the centering assembly 4 are made of a non-metal conductive material.

When the spray nozzle is used, the problems of powder sticking at the bottom of the inner core and powder accumulation falling can be avoided, powder accretion generated on a sprayed product due to the falling powder accumulation can be avoided, the surface powder of the sprayed product is ensured to be uniform, and the unqualified rate of the sprayed product is effectively reduced; in addition, the inner core can be cooled, and the situation that powder is easier to adhere due to the temperature rise of the inner core is prevented.

The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the invention should be considered within the scope of the invention. It should be noted that the components of the present invention are not limited to the above-mentioned whole application, and various technical features described in the present specification can be selected from one or more of the components to be used alone or in combination according to actual needs, so that the present invention naturally covers other combinations and specific applications related to the invention.

Claims

1. A powder spray gun, comprising:

the spray gun comprises a gun body, a spray gun head and a spray gun tail, wherein the two ends of the gun body are respectively provided with the spray gun head and the spray gun tail;

the powder conveying pipe comprises an inner section and an outer section, the inner section penetrates through the gun body, the outer section is arranged outside the gun body and can be connected with a powder supply system, the inner section extends from the tail of the spray gun to the head of the spray gun and is communicated with a spray nozzle of the spray gun, and a gas inlet is formed in the side wall of the outer section;

a gas delivery pipe for carrying secondary atomizing gas, gas delivery pipe with gas inlet connects and communicates, secondary atomizing gas that gas delivery pipe carried is followed gas inlet spouts into in the outer section, spout into secondary atomizing gas in the outer section with the primary atomized powder that outer section was carried is towards the in-process that the spray gun spout flows mixes and forms secondary atomized powder.

2. The powder spray gun of claim 1 wherein a portion of said outer section between said gas inlet and said gun tail is 0 to 2000mm in length.

3. A powder spraygun as claimed in claim 1, wherein the gas feed tube is arranged obliquely with respect to the outer section, the angle between the inlet direction of the gas feed tube and the outer section being between 10 ° and 90 °.

4. The powder spray gun of claim 1, wherein the gas inlet has an offset distance from a center of the powder delivery pipe in a radial direction of the powder delivery pipe, the offset distance being 0 to 5 mm.

5. The powder spray gun of any one of claims 1 to 4 further including a nozzle at a nozzle opening of the spray gun and a gas conduit extending into the gun body outside the interior section;

the nozzle comprises an annular outer sleeve and an annular inner core fixed in the outer sleeve, the outer sleeve is connected with the inner section of the powder conveying pipe, a cavity communicated with the inner section and used for the secondary atomized powder to pass through is formed between the outer sleeve and the inner core, and an annular spraying port communicated with the cavity is formed between the bottom edge of the outer sleeve and the bottom edge of the inner core; the side wall of the outer sleeve is provided with an air inlet hole, the air guide tube is communicated with the air inlet hole, an airflow channel is axially arranged inside the inner core and is communicated with the air inlet hole, the bottom surface of the inner core is provided with an air jet communicated with the airflow channel, and the air jet is surrounded by the material spraying hole.

6. A powder spraygun as claimed in claim 5, wherein a plurality of said air inlet holes are provided in the side wall of the outer sleeve, an annular chamber is provided in the side wall of the spraygun head, the annular chamber surrounds the plurality of said air inlet holes and communicates with the plurality of said air inlet holes, the air duct extends from the rear of the spraygun into the side wall of the gun body to the annular chamber, and the air duct communicates with the plurality of said air inlet holes through the annular chamber.

7. The powder spray gun as claimed in claim 5, wherein the outer sleeve includes a first sleeve body and a second sleeve body which are separately provided, the first sleeve body has a first through hole axially penetrating in the center thereof, the second sleeve body has a second through hole axially penetrating in the center thereof, the air inlet is provided on the side wall of the first sleeve body or the second sleeve body, and the first sleeve body is connected with the inner section of the powder delivery pipe;

the nozzle also comprises a centering assembly, the centering assembly comprises a positioning cylinder and a positioning core which is fixed in the positioning cylinder and is coaxially arranged with the positioning cylinder, at least one axially-through feeding channel is arranged between the positioning cylinder and the positioning core, the upper end of the positioning cylinder is coaxially connected with the first sleeve, the lower end of the positioning cylinder is coaxially connected with the second sleeve, the feeding channel is communicated with the first through hole and the second through hole, an air inlet channel communicated with the air inlet hole is arranged in the centering assembly, and the air inlet channel is not communicated with the feeding channel;

the inner core is arranged in the second through hole, the upper end of the inner core is coaxially connected with the lower end of the positioning core, the cavity is formed between the inner core and the second sleeve body and is communicated with the feeding channel, and the airflow channel is communicated with the air inlet channel.

8. The powder spray gun as set forth in claim 7, wherein said positioning cylinder and said positioning core are connected by one or more wings, and when the number of said wings is plural, the plural wings are arranged at intervals in the circumferential direction of said positioning cylinder, and the plural wings divide an annular space between said positioning cylinder and said positioning core into plural said feed passages, said feed passage passing through said positioning cylinder and said wings in the radial direction.

9. The powder spray gun of claim 7, wherein the lower portion of the second sleeve body is a flared first gradually expanding portion having an inner diameter gradually expanding in the flow direction of the secondary atomized powder, the lower portion of the inner core is a flared second gradually expanding portion having an outer diameter gradually expanding in the flow direction of the secondary atomized powder, and the nozzle opening is formed between a bottom edge of the first gradually expanding portion and a bottom edge of the second gradually expanding portion; the air injection port is a tapered hole with the inner diameter gradually expanding along the airflow direction.

10. A powder spray gun as claimed in claim 5, wherein the nozzle is made of a metallic conductive material and is connected to the electrostatic generator by electrical wiring.